code: def setUp(self):
      self.vertices = pd.DataFrame(
          {
              "vid": ["1", "2", "3"],
              "color": ["g", None, "b"],
              "vec": [
                  [0.1, 0.1, 0.1],
                  [0.1, 0.1, 0.1],
                  [0.1, 0.1, 0.1],
              ],
          }
      )
      self.edges = pd.DataFrame(
          {
              "src_id": ["1", "2", "3"],
              "dst_id": ["2", "3", "4"],
              "weight": [0.0, None, 1.0],
          }
      )
  
imports: from __future__ import print_function
  from __future__ import division
  from __future__ import absolute_import
  from ..data_structures.sgraph import SGraph, Vertex, Edge, load_sgraph
  from ..data_structures.sframe import SFrame
  from .None import util
  import pandas
  from pandas.util.testing import assert_frame_equal
  import numpy
  import unittest
  import tempfile
  import json
  import os
  import sys
  import pytest
label_desc: Use image node_id 1 for calling the GraphTests obj's underlying member method code with example usage: obj.setUp() without return types